In statistics the term “population” has a slightly different meaning from the one given to it in ordinary speech. It need not refer only to people or to animate creatures – the population of Britain, for instance or the dog population of London. Statisticians also speak of a population of objects, or events, or procedures, or observations, including such things as the quantity of lead in urine, visits to the doctor, or surgical operations. A population is thus an aggregate of creatures, things, cases and so on.
